MUSIC SINCE THE BEGINNING OF TIME

As humans, we all share one unique feature – the ability to produce and enjoy music. Music is not a new concept though. More than 165,000 years ago, our ancestors have already invented percussion instruments. Today, all societies and cultures have music. With these ancient roots, music undoubtedly plays a signi!cant part in our lives today. Over the past ten years, a record number of 297 million Apple IPods alone have been sold around the world. There are reasons for our fondness for music. Music a"ects our emotions and activates certain brain areas, the same centers of the brain for food and drug addictions. It seems that our appreciation for music is innate. Infants, even as young as two months old, turn to pleasant sounds, but away from dissonant, harsh, sounds. This fasci-nation of music has made many scientists ponder – does music a"ect more than our emotions? Does music physically change the brain and a"ects our intelligence?

THE MOZART EFFECT

Perhaps one of the most well-known and arguably most controversial phenomena is the Mozart E"ect. The term was !rst coined by Dr. Afred Tomatis, who suggested that listening to compositions of Mozart increases a child’s IQ. This idea has been so favorable and popularized that the Governor of Georgia, Zell Miller, even proposed a budget to provide all children in Georgia with a CD of classical music. However, there has been great controversy among the scienti!c community as numerous studies have failed to replicate this !nding. Whether music improves intelligence in children remains to be elucidated. However, a new area of research is not studying music in childhood, but music in the womb. At late gestational stage, the fetus can hear sounds from outside the mother, and from these sounds, can become familiarize to her voice. After birth, the infant can .....................`

This fascination of music has made many scientists ponder –

Does music physically change the brain and affects our intelligence?

distinguish the mother’s voice from others. Since sound plays a role in the development of the fetus in the womb, a central question has arised - does music a"ect fetal develop-ment?

RESEARCH IN ANIMAL MODELS

Since it is di#cult, unethical and impractical to perform studies on human fetus, much research has been concentrated on the animal model. Whether animals have the same appreciation for music is debatable, but a few studies have found an e"ect on pre-natal auditory stimula-tion. One study looked at whether pre-natal auditory stimulation a"ects spatial memory in rats. The researchers exposed pregnant mothers to noise or music for an hour a day until delivery and tested the pubs’ navigational ability in a maze test after birth. They found that the group stimulated with pre-natal music took much less time to !nd food in a maze compared with the group with no stimulus or the

group stimulated with random noise. Interestingly, the group stimulated with random noise performed even worse than the unstimulated group, suggesting it is music, and not random noise, which contributed to the improvement in spatial memory. Similar studies in di"erent animal models have been replicated to correlate prenatal music stimulation with enhancement of spatial learning. In another study, music or no stimulation was provided to fertilized chick eggs. Follow-ing hatching, the chicks were trained to perform a similar maze task to test for memory. The researchers found that music-stimulated chicks took less time to reach the target compared with the un-stimulated group. These studies, taken together, suggest that pre-natal auditory stimulation does have an e"ect on learning, at least in the animal model. However, what is the underlying mechanism for these enhancements, and are these changes due to the brain being structurally altered?

MUSIC, INTELLIGENCE, AND BABIES - CAN WE LINK THESE TOGETHER?

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NEW NEURONS IN MEMORY CENTER OF THE BRAIN

Numerous studies have found that pre-natal expo-sure to music in the animal model increases neurogenesis, the birth of neurons, in the memory-center of the brain, the hippocampus. The hippocampus is a major brain structure present in all mammals involved in the consolidation of short-term to long-term memory, and in spatial navigation. Damages to this area of the brain result in memory loss. Alzheimer’s disease is an example where the loss of memory is largely attributed to damages at the hippocampus. On the contrary, studies have found that increased neurogenesis at the hippocampus enhances memory. Rats stimulated by music before birth display an increase in the birth of neurons at the hippocampus, and an improvement in spatial memory. At the molecular level, music upregulates the expression of proteins involved in the survival of neurons, such as CREB, p-CREB, and BDNF. Music may stimu-late an improvement in memory through the increase in neurons at this brain area. The number of synapses of the neurons also increases at the hippocampus. The synapse is a junction that allows neurons to pass chemical signals to another cell for communication. Thus, a neuron with more synapses would be communicating with more neurons. A higher synaptic density has been correlated with improvement in memory. Having neurons that are talking to other neurons more seem to improve spatial memory. Perhaps pre-natal music stimula-tion changes the expressions of proteins at the molecular level, which allows more neurons to be born and to commu-nicate with one another, leading to an enhancement in spatial memory.

DIRECT OR INDIRECT EFFECTS OF MUSIC?

The mechanism proposed above is that auditory stimulation directly increases neurogenesis at the hippo-campus by changing protein levels, leading to an enhance-ment in memory. However, many debates have been on whether these changes in brain structure are due to indirect e!ects of music. Perhaps music leads to a secondary e!ect that causes these di!erences. One such e!ect is the lowering of stress. Music is known to be a reliever for stress and anxiety. Music therapy is widely used and is e!ective in alleviating these symptoms.

The e!ect of music reducing stress and anxiety is also present in pregnant mothers. In a study conducted at the College of Nursing at Kaohsiung Medical University, Taiwan, the researchers recruited 236 pregnant women in their second or third trimester, all with similar backgrounds in occupation, class, education level, and marital happiness. Half were given CDs and listened to music for half an hour each day. They were given the choice of listening to classical music, nature sounds, Chinese children’s rhymes and songs,

or lullabies. The other half did not listen to the CD. Although both groups received the same routine prenatal care, moth-ers who listened to music had a lower level of stress, anxiety, and depression scores even only after two weeks. As the study’s author, Dr. Chung-Hey Chen, explained in a news release, “Our study shows that listening to suitable music provides a simple, cost-e!ective and non-invasive way of reducing stress, anxiety and depression during pregnancy.”

Although both groups received the same routine prenatal care, mothers who listened to music had a lower level of stress, anxiety, and depression scores even only after two weeks.

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Stress is bene!cial during evolutionary develop-ment. In the body, stress upregulates a hormone, cortisol, which leads to the body’s “!ght or "ight” response. Cortisol heightens energy metabolism, and suppresses non-immediately needed processes, like immunity and reproduc-tion. However, long-term exposure to cortisol leads to nega-tive e#ects, such as impaired cognitive performance, lowered immunity and infertility. A high level of cortisol is correlated with increased cell death at the hippocampus.

Pre-natal stress is also linked to learning de!cits. O#spring from pregnant rodent mothers exposed to stress perform poorer in spatial memory tasks. Pre-natal stress a#ects the o#spring in adolescents and even well into adult-hood. Not only is spatial memory altered, but the brain morphology is also changed. The animals display a reduced cell growth and accelerated aging in the hippocampus. Furthermore, researchers found more cells dying and under-going degeneration at this brain region. In these animals, the adrenal gland, the source for cortisol, also increased in size, suggesting that the e#ects in the brain may be because of an increase in stress hormone in the body. Pre-natal stress a#ects neurogenesis at the hippocampus through an increase in cortisol, which leads to poorer performance in spatial memory. This is the opposite e#ect of music, which increases neurogenesis and enhances spatial memory, a medium that also reduces stress and anxiety. Perhaps music indirectly a#ects the growing fetus by lowering stress and cortisol in the mother, rescuing these new-born neurons and leading to enhancements in spatial memory. MUSIC ALTERS STEROID HORMONES

Cortisol may not be the only hormone that music a#ects. Steroid hormones, androgens and estrogens, are suggested to be involved. While androgens are usually referred to as male hormones and estrogens as female hormones, we all possess both types. After listening to music, men have a lower level of androgens, but women have a higher level of these hormones. Estrogen level is also altered by musical stimulation. It has been suggested that music changes our mood, leading to alterations in the levels of steroid hormones in our body.

Both androgens and estrogens are involved in the organization of neurons in the brain. Estrogens regulate important molecules that promote the growth of neurons, such as brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) Androgens also increase NGF. In fact, music increases neurogenesis, the regeneration and repair of neurons in the adult brain by altering androgen and estro-gen levels. Therefore, music may also enhance spatial memory by indirectly altering levels of these hormones in

the body, which leads to changes in protein levels at the hippocampus. Our brains are a#ected by many chemicals. Cortisol and steroid hormones are only a few that have an e#ect on neurons. There may be many more chemicals involved to explain music’s e#ect on the enhancement in spatial memory.

In fact, music increases neurogenesis, the regeneration and repair of neurons in the adult brain by altering androgen and estrogen levels.

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SIGNIFICANCE IN HUMAN

Music improves spatial memory in rodents and other animal models. However, one criticism is that humans expe-rience and appreciate music di!erent than animals. Can these non-human studies be applied to us? While there are no studies that look at stimulating pregnant human mothers with music and performing tests on infants, studies do suggest a correlation between musi-cians and spatial memory. Furthermore, musical training has been found to enhance spatial recognition tasks in pre-school children and improve their learning of math-ematics and science. While these e!ects may be attributed to training and not listening itself, music does seem to have a bene"cial e!ect.

TO LISTEN OR NOT TO LISTEN

To a pregnant mother, the most important ques-tion may be, “Should I listen to music then?”. While we do not know whether music directly or indirectly a!ect the brain in animal studies, music does alleviate pre-natal stress, which is at least bene"cial for the mother. As of now, there are no studies that demonstrate a correlation between music and negative e!ects. Music also minimizes the distress of labor. While controversies remain on the e!ects of prenatal musical stimulation on intelligence, there are no doubts that music bene"ts the mother. A mother should not listen to music.............

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expecting to increase a child’s intelligence, but listen for her own enjoyment and bene"ts. Who knows, maybe listening to Wagner helps you relax and give birth to the next Einstein. As Shakespeare wrote, “If music be the food of love, play on”!

Chang, M.Y., Chen, C.H., and Huang, K.F., 2008, E!cts of music therapy on psycho-logical health of women during pregnancy: J Clin Nurs, v.17, p2580-7.

Chaudhury, S., and Wadhwa, S., 2009, Prenatal auditory stimulation alters the levels of CREB mRNA, p-CREB and BDNF expression in chick hippocampus: Int J Dev Neurosci, V.27, p.583-90.

Fukui, H., and Toyoshima, K., 2008, Music facilitate the neurogenesis, regeneration and repair of neurons: Med Hypotheses, v.71, p.765-9.

Kauser, H., Roy, S., Pal, A., Sreenivas, V., Mathur, R., Wadhwa, S., and Jain, S., 2011, Prenatal complex rhythmic music sound stimulation facilitates postnatal spatial learning but transiently impairs memory in the domestic chick: Dev Neurosci, v.33, p.48-56.

Kim, H., Lee, M.H., Chang, H.K., Lee, T.H., Lee, H.H., Shin, M.C., Shin, M.S., Won, R., Shin, H.S., and Kim, C.J., 2006, In#uence of prenatal noise and music on the spatial memory and neurogenesis in the hippocampus of developing rats: Brain Dev, v.28, p.109-14.

Lemaire, V., Koehl, M., Le Moal, M., and Abrous, D.N., 2000, Prenatal stress produces learning de"cits associated with an inhibition of neurogenesis in the hippocampus: Proc NatI Acad Sci USA, v.97, p.11032-7.

Rauscher, F.H., Shaw, G.L., Levine, L.J., Wright, E.L., Dennis, W.R., and Newcomb, R.L., 1997, Music training causes long-term enhancement of preschool children’s spatial-temporal reasoning: Neurol Res, v.19, p.2-8.

Tabarro, C.S., de Campos, L.B., Galli, N.O., Novo, N.F., and Pereira, V.M., 2010, E!ects of the music in labor and newborn. Rev Esc Enferm USP, v.44, p.445-52

More to Explore

While controversies remain on the effect of prenatal musical stimulation on intelligence, there are no doubts that music benefits the mother.

A mother should not listen to music expecting to increase a child’s intelligence, but listen for her own enjoyment and benefits.

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